Compression release for motorcycle engines

ABSTRACT

A one-way compression release for two-cycle motorcycle engines. A body has an elongated valve stem which is movable to open a valve member connected with the cylinder of an engine. When the valve member is opened, gas moves under pressure from the cylinder through a chamber surrounding the valve stem and out through openings in the body to the atmosphere. A resilient member mounted on the outside of the body in overlying relationship to the openings is flexed outwardly to permit the gas to be vented to the atmosphere. The resilient member acts as a check valve to prevent reverse movement of gases when the main valve member is open and as a sealer to prevent contaminants from entering the chamber when the main valve member is closed.

United States Patent Bonewitz l COMPRESSION RELEASE FOR MOTORCYCLE ENGINES [75] Inventor: Everett D. Bonewitz, Santa Fe Springs, Calif.

[73] Assignee: Victor Plastics, Inc., Santa Fe Springs, Calif.

[22] Filed: Dec. 26, 1973 [21] Appl. No.: 428,040

[ June 10, 1975 Primary Examiner-Charles J. Myhre Assistant Examiner-W. Rutledge, Jr. Attorney, Agent, or FirmRobert C. Comstock [57] ABSTRACT A one-way compression release for two-cycle motorcycle engines. A body has an elongated valve stem which is movable to open a valve member connected with the cylinder of an engine. When the valve member is opened, gas moves under pressure from the cylinder through a chamber surrounding the valve stem and out through openings in the body to the atmosphere. A resilient member mounted on the outside of the body in overlying relationship to the openings is flexed outwardly to permit the gas to be vented to the atmosphere. The resilient member acts as a check valve to prevent reverse movement of gases when the main valve member is open and as a sealer to prevent contaminants from entering the chamber when the main valve member is closed.

8 Claims, 8 Drawing Figures PATENTEUJUMIU 1975 8888.218

1 16.1. Z4'\\ .FZIG. 2.

COMPRESSION RELEASE FOR MOTORCYCLE ENGINES BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to a one-way compression release which is particularly adapted for use on two-cycle internal combustion engines of the type now used in motorcycles 2. Description of the Prior Art One way compression releases of the type now in use are exemplified by those shown and described in prior patents to Boling US. Pat. No. 3,638,632 and Bygdnes US. Pat. No. 3,667,435. Such compression releases have a major deficiency in that the outlet or discharge openings are open to the atmosphere at all times, permitting dust, dirt, oil and other undesirable contaminants to enter into the interior chamber of the compression release.

Even though such compression releases have internal poppet or check valves, such check valves are not completely effective in keeping out undesirable contaminants. The releases accordingly often utilize fine mesh filters, which are necessarily expensive because they must be formed of material which can withstand extremely high temperatures as well as corrosive gases.

SUMMARY OF THE INVENTION The invention comprises a one-way compression release which is particularly adapted for use on motorcycle engines and which overcomes substantially all of the deficiencies of presently existing compression releases.

It is a particular object of the invention to provide such a release which completely'excludes dust. dirt and other contaminants from entering the release or entering the engine by way of the release.

Another object of the invention is to provide such a release in which internal check valves and fine mesh filters can both be eliminated. Elimination of these parts means that the body of the release can be formed of one part instead of two.

These changes result in a release which is far more simple in construction and operation and which is more economical. so that it can be made and sold at a substantially lower price.

The invention contemplates a compression release in which the outlet openings are removably covered by a resilient member which is capable of withstanding high temperature of the type existing in such releases. In a first preferred embodiment of the invention, such a resilient member comprises an O-ring or similar annular member formed of resilient material. In a second preferred embodiment. it comprises a resilient flap or COVEI'.

In both embodiments, the resilient member completely covers the outside of the outlet openings when they are not in use, thus preventing dust, dirt and contaminants from entering the release and engine. When the release is used, the pressure of gases passing through the outlet openings acts to temporarily move the resilient member away from the openings while the gas escapes. The resilient member thereafter automatically moves back by its own resilience into a position covering the outlet openings.

It is accordingly among the objects of the invention to provide a compression release having all of the advantages and benefits of the structure set forth above and described in detail hereinafter in this specification.

The invention also comprises such other objects, ad vantages and capabilities as will later more fully appear and which are inherently possessed by the invention.

While I have shown in the accompanying drawings preferred embodiments of the invention, it should be understood that the same are susceptible of modification and change without departing from the spirit of the invention.

DESCRIPTION OF THE DRAWINGS Referring to the drawings:

FIG. I is a side elevational view of a compression release in use;

FIG. 2 is an enlarged transverse sectional view of the outlet opening portion thereof taken along line 22 of FIG. 1;

FIG. 3 is an enlarged partial longitudinal sectional view of the lower portion of the release taken along line 3-3 of FIG. 3;

FIG. 4 is an enlarged longitudinal sectional view similar to FIG. 3 ofan alternative embodiment of the invention;

FIG. 5 is atop view of the same taken along line S5 of FIG. 4;

FIG. 6 is a partial sectional view of another alternative embodiment in which a secondary groove is disposed beneath an O-ring;

FIG. 7 is a partial sectional view similar to FIG. 2 showing an alternative embodiment in which the outlet opening comprises a single slit;

FIG. 8 is a partial sectional view of still another alternative embodiment in which the resilient member comprises a flat band extending around the midportion of the body.

DESCRIPTION OF THE PREFERRED EMBODIMENT A first preferred embodiment which has been selected to illustrate the invention is shown in FIGS. l3 of the drawings. It comprises a body 10, which may conveniently be formed from hex bar stock. An elongated valve stem ll extends through the body 10 along its longitudinal axis. The lower end of the valve stem I 1 comprises a bevelled valve member 12 which is normally held in close engagement with a valve seat 13 formed on the lower end of the body 10. A coil spring 14 which extends between the top of the body 10 and a knob 15 mounted on the upper end of the valve stem 11 acts to normally hold the valve member l2 in closed position.

One side of the body 10 is provided with a keyhole slot 16 for receiving a ball 17 carried by the lower end of a control cable I8. An annular spring 9 fits within a groove in the upper portion of the body 10 to hold the cable 18 and ball 17 in place.

The compression release is customarily mounted on the motorcycle with the lower end of the body threadedly mounted in the motorcycle cylinder head. The end of the cable 18 remote from the body 10 is connected to a manually operable lever adjacent to the handlebars (not shown in the drawings). The lever may be operated by the driver to depress the knob 15 and valve stem 11 against the pressure of the coil spring I4. Downward movement of the valve stem 11 moves the valve member 12 downwardly into open position with respect to the valve seat 13.

The midportion of the body is provided with two pairs of diametrically spaced outlet openings 19, which in the present invention may comprise holes, slits, slots or any other suitable form of opening. The openings 19 extend into a chamber within the body 10 which surrounds the midportion of the valve stem 11.

All of the foregoing structure is conventional and the method of operation of such compression releases is well known to those skilled in the art and is set forth in detail in the above-mentioned patents.

The novel structure of the present invention com' prises in this first embodiment an annular groove which extends around the midportion of the body 10. The outlet openings 19 are preferably formed so that their outer ends are disposed in alignment with the bottom of the groove 21. Mounted within the groove 21 is a resilient O-ring 23, which is preferably formed of elastomeric material such as silicone or other material which is capable of resisting the withstanding for an extended period of time high temperatures of the type existing in the body 10 and the gases passing through the openings 19. Such temperatures are in the range of approximately 300 F.

The bottom of the groove 21 is preferably substantially concentric with the exterior ciircumference of the inner portion of the O-ring 23, so that the O-ring 23 acts to provide a complete sealing of the outer ends of the openings 19.

In operation, when the lever is operated by the driver to depress the valve stem 11 and open the valve member 12, gas flows inwardly through the open space between the valve member 12 and valve seat 13. This gas is driven out of the cylinder by the increased pressure resulting from combustion within the cylinder. The gas moves upwardly through the chamber 20 surrounding the body 10 and then moves outwardly through the outlet openings 19, causing the O-ring 23 to be flexed away from the bottom of the groove 21. This continues until the diminished pressure within the cylinder develops into a partial vacuum, at which time the O-ring 23 is drawn inwardly toward the bottom of the groove, forming a seal against the outer ends of all of the open ings 19. The (lring 23 thereby prevents undesirable movement of dust, dirt and other contaminants into the compression release and cylinder.

It will be noted that the O-ring 23 serves a double function. When the main valve member 12 is closed, the O-ring 23 operates as a check valve comparable to those shown and described in the above-mentioned prior patents. When the main valve member is closed, the O-ring 23 acts as a seal to prevent contaminating material from entering the compression release and cylinder. as is possible in the prior art structures which have no sealing means disposed around the outer ends of the outlet openings.

The sides of the groove 21 should preferably be sufficiently shallow and angled so that when the O-ring 23 is moved outwardly by the pressure of gas exerted through the outlet openings 19, the O-ring 23 will not be flattened into an elliptical configuration and form a seal extending across the width of the groove 21. If this should occur, the O-ring 23 is likely to be blown com pletely out of the groove 21.

For this reason, it is believed that the sides of the groove should have an agle in excess of 15 and preferably in the range of approximately 30.

The portions of the body 10 which are disposed on both sides of the groove 21, should preferably be somewhat rounded away from the groove so that the O-ring 23 in its movement within the groove 21 will not encounter sharp edges. Such sharp edges are likely to cut the O-ring 23 and result in its failure.

In order to assist in mounting the O-ring 23 in the groove 21 without cutting or damaging the O-ring 23, the normally hexagonal portion 24 of the body 10 which is disposed adjacent to the groove 21 should have all of its corners cut and rounded off to form a twelve-sided shape. The O-ring 23 can then be safely passed over the portion 24.

As shown in FIG. 6 of the drawings. the body 10 may be provided with a secondary groove 31 of substantially smaller diameter. the purpose of which is to provide a path for the gas pressure to move around beneath the O-ring 23 so that the pressure is not entirely concentrated at the outer ends of the outlet openings 19. This provides a more even expansion of the O-ring 23 and acts to prevent any accidental blow-out of the O-ring 23 from the groove 21.

A second preferred embodiment of the invention is shown in FIGS. 45 of the drawings. The conventional portions of the compression release are substantially identical with those of the first embodiment.

In this second embodiment, the body is provided with a plurality of slots 190 which extend inwardly from the top of the body 100 to the chamber 20a which surrounds the valve stem 11a.

A resilient annual sealing member 23a is mounted on the top of the body 10a so that it is normally in overlying and sealing relationship to the outer ends of the outlet openings 19a. Any suitable means may be used for attaching the sealing member 23a to the body 10a. As shown in the drawings, the two members may be adhered together around the outer periphery of the sealing member 23. Suitable mechanical attaching means of any kind may also be used, preferably extending around the periphery of the sealing member 23a, leaving the inner portion free to flex away from the body 10a.

This embodiment of the invention functions in substantially the same manner described above. When the valve member 12a is in open position, gas moves under pressure from the cylinder through the slots 19a. The pressure of this gas causes the inner portion of the sealing member 23a to flex away from the body 10a, opening the outer ends of the slots 19a and permitting the gas escaping to the atmosphere. As soon as the pressure ceases. the sealing member 23a will automatically return by its own resilience into a sealing relationship with the outer ends of the slots 19a. The sealing member 230 should be formed of suitable heat and corro sion resistant material.

FIG. 7 of the drawings shows an alternative embodiment of the invention in which the outlet opening comprises a single slit 19b approximately l/l6 inch in thickness and extending for approximately around the groove.

FIG. 8 of the drawings shows another alternative embodiment of the invention in which the resilient member comprises a substantially flat resilient band 230 which fits within a relatively shallow groove 21c extending around the body. Instead of fitting in a groove, the band 23c may be mechanically or adhesively attached to the body along its upper or lower edge.

In some types of motorcycle racing, the driver prefers to have a two-way release instead of a one-way release. The embodiments of the present invention in which the resilient member comprises an annular O-ring or band are particularly adapted for simple conversion into a twoway release by merely removing the O-ring or band from the body.

l claim:

1. In a compression release for an internal combustion engine of the type having a body with a chamber therein connected to the engine, a valve member operable to open and close the connection between said chamber and engine, and at least one outlet opening in said body for venting gases passing into said chamber from the engine when said valve member is open, the improvement comprising a resilient high temperature and corrosion resistant annular O-ring overlying said outlet opening, said O-ring being mounted in a complementary groove extending around the outer periphery of said body, said outlet opening intersecting the inner most portion of said groove, said O-ring normally sealing off said outlet opening to prevent contaminants from entering said chamber, said O-ring and groove being constructed and arranged so that said O-ring is movable outwardly under the sudden application of high pressure from gases moving into said chamber when said valve member is open without said o-ring becoming unseated from said groove, said O-ring automatically flexing back to its normal position sealing said outlet opening when the pressure in said chamber is removed, said O-ring acting as a check valve to prevent the reverse movement of gases and impurities into said engine.

2. The structure described in claim 1, said groove being substantially equal in depth to the diameter of said O-ring, said groove having symmetrical outwardly flared sides so that gases flow equally on opposite sides of said O-ring to prevent unseating of said O-ring from said groove.

3. The structure described in claim 2, the sides of said groove having an angle in excess of 15 degrees.

4. The structure described in claim 3, the sides of said groove having an angle of approximately 30.

5. The structure described in claim 4, said O-ring being formed of silicone rubber.

6. The structure described in claim 5, said body having a plurality of diametrically opposed outlet openings intersecting the bottom of said groove.

7. The structure described in claim 4, said body having a second annular groove of smaller diameter than said first named groove, said second groove being disposed between said first named groove and said outlet opening.

8. The structure described in claim 4, said outlet opening comprising at least one elongated arcuate slit extending through said body and intersecting the lower portion of said groove. 

1. In a compression release for an internal combustion engine of the type having a body with a chamber therein connected to the engine, a valve member operable to open and close the connection between said chamber and engine, and at least one outlet opening in said body for venting gases passing into said chamber from the engine when said valve member is open, the improvement comprising a resilient high temperature and corrosion resistant annular Oring overlying said outlet opening, said O-ring being mounted in a complementary groove extending around the outer periphery of said body, said outlet opening intersecting the inner most portion of said groove, said O-ring normally sealing off said outlet opening to prevent contaminants from entering said chamber, said O-ring and groove being constructed and arranged so that said O-ring is movable outwardly under the sudden application of high pressure from gases moving into said chamber when said valve member is open without said o-ring becoming unseated from said groove, said O-ring automatically flexing back to its normal position sealing said outlet opening when the pressure in said chamber is removed, said O-ring acting as a check valve to Prevent the reverse movement of gases and impurities into said engine.
 2. The structure described in claim 1, said groove being substantially equal in depth to the diameter of said O-ring, said groove having symmetrical outwardly flared sides so that gases flow equally on opposite sides of said O-ring to prevent unseating of said O-ring from said groove.
 3. The structure described in claim 2, the sides of said groove having an angle in excess of 15 degrees.
 4. The structure described in claim 3, the sides of said groove having an angle of approximately 30*.
 5. The structure described in claim 4, said O-ring being formed of silicone rubber.
 6. The structure described in claim 5, said body having a plurality of diametrically opposed outlet openings intersecting the bottom of said groove.
 7. The structure described in claim 4, said body having a second annular groove of smaller diameter than said first named groove, said second groove being disposed between said first named groove and said outlet opening.
 8. The structure described in claim 4, said outlet opening comprising at least one elongated arcuate slit extending through said body and intersecting the lower portion of said groove. 